Beyond the Known Universe

Ringworld 

by Larry Niven

 

“I myself have dreamed up a structure intermediate between Dyson spheres and planets. Build a ring 93 million miles in radius - one Earth orbit - around the sun. If we have the mass of Jupiter to work with, and if we make it a thousand miles wide, we get a thickness of about a thousand feet for the base. 
And it has advantages. The Ringworld will be much sturdier than a Dyson sphere. We can spin it on its axis for gravity. A rotation speed of 770 m/s will give us a gravity of one Earth normal. We wouldn't even need to roof it over. Place walls one thousand miles high at each edge, facing the sun. Very little air will leak over the edges. 
Lord knows the thing is roomy enough. With three million times the surface area of the Earth, it will be some time before anyone complains of the crowding.”  ― Larry Niven

This is certainly one of the best science fiction novels that I have read. I say that because of the lucid and concise writing style, the use of scientific concepts in a way that exceeds most SF novels, and the brilliant imagination of Larry Niven who creates aliens and other worlds and puts you the reader into them with confidence and grace. In the opening sections of the story Louis Wu, a two hundred year-old human is confronted by Nessus, a Pierson's Puppeteer, and offered one of three open positions on an exploration voyage beyond Known Space. Speaker-to-Animals (Speaker), who is a Kzin, and Teela Brown, a young human woman, also join the voyage. Their goal is "Ringworld":

"The ring was more than ninety million miles in radius---about six hundred million miles long, he estimated---but less than a million miles across, edge to edge.  It massed a little more than the planet Jupiter."(p 80)

Once the four travelers arrive at the Ringworld the novel becomes a more picaresque tale of their adventures. In spite of this the plot itself had several exciting moments with the group on the proverbial brink of disaster. This novel set in Niven's "Known Space" universe is considered a classic of science fiction literature. It was followed by three sequels, preceded by four prequels, and ties into numerous other books set in Known Space. Many of the concepts displayed in Ringworld were originally presented in earlier novels by the author. The Nebula award-winning novel still retains its ability to charm the reader.

Ringworld by Larry Niven. Ballantine Books, 1971 (1970)